Canadian Aerosol Module: A size-segregated simulation of atmospheric aerosol processes for climate and air quality models 1. Module development

Atmospheric sulfate aerosols have important impacts on air quality, climate, and human and ecosystem health. However, current air-quality models generally underestimate the rate of conversion of sulfur dioxide (SO2) to sulfate during severe haze pollution events, indicating that our understanding of sulfate formation chemistry is incomplete. This may arise because the air-quality models rely upon kinetics studies of SO2 oxidation conducted in dilute aqueous solutions, and not at the high solute strengths of atmospheric aerosol particles. Here, we utilize an aerosol flow reactor to perform direct investigation on the kinetics of aqueous oxidation of dissolved SO2 by hydrogen peroxide (H2O2) using pH-buffered, submicrometer, deliquesced aerosol particles at relative humidity of 73 to 90%. We find that the high solute strength of the aerosol particles significantly enhances the sulfate formation rate for the H2O2 oxidation pathway compared to the dilute solution. By taking these effects into account, our results indicate that the oxidation of SO2 by H2O2 in the liquid water present in atmospheric aerosol particles can contribute to the missing sulfate source during severe haze episodes.

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A computationally-efficient secondary organic aerosol module for three-dimensional air quality models

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-7085-2008 ◽

2008 ◽

Vol 8 (2) ◽

pp. 7085-7110

Author(s):

P. Liu ◽

Y. Zhang

Keyword(s):

Air Quality ◽

Organic Compounds ◽

Activity Coefficients ◽

Three Dimensional ◽

Computationally Efficient ◽

Quality Models ◽

Organic Mixtures ◽

Speed Up ◽

Numerical Solver ◽

Aerosol Module

Abstract. Accurately simulating secondary organic aerosols (SOA) in three-dimensional (3-D) air quality models is challenging due to the complexity of the physics and chemistry involved and the high computational demand required. A computationally-efficient yet accurate SOA module is necessary in 3-D applications for long-term simulations and real-time air quality forecasting. A coupled gas and aerosol box model (i.e., 0-D CMAQ-MADRID 2) is used to optimize relevant processes in order to develop such a SOA module. Solving the partitioning equations for condensable volatile organic compounds (VOCs) and calculating their activity coefficients in the multicomponent mixtures are identified to be the most computationally-expensive processes. The two processes can be speeded up by relaxing the error tolerance levels and reducing the maximum number of iterations of the numerical solver for the partitioning equations for organic species; turning on organic-inorganic interactions only when the water content associated with organic compounds is significant; and parameterizing the calculation of activity coefficients for organic mixtures in the hydrophilic module. The optimal speed-up method can reduce the total CPU cost by up to a factor of 29.7 with ±15% deviation from benchmark results. These speedup methods are applicable to other SOA modules that are based on partitioning theories.

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Continued development and testing of a new thermodynamic aerosol module for urban and regional air quality models

Atmospheric Environment ◽

10.1016/s1352-2310(98)00352-5 ◽

1999 ◽

Vol 33 (10) ◽

pp. 1553-1560 ◽

Cited By ~ 212

Author(s):

Athanasios Nenes ◽

Spyros N. Pandis ◽

Christodoulos Pilinis

Keyword(s):

Air Quality ◽

Quality Models ◽

Regional Air Quality ◽

Aerosol Module

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A computationally-efficient secondary organic aerosol module for three-dimensional air quality models

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-3985-2008 ◽

2008 ◽

Vol 8 (14) ◽

pp. 3985-3998 ◽

Cited By ~ 4

Author(s):

P. Liu ◽

Y. Zhang

Keyword(s):

Air Quality ◽

Activity Coefficients ◽

Three Dimensional ◽

Computationally Efficient ◽

Quality Models ◽

Organic Mixtures ◽

Speed Up ◽

Numerical Solver ◽

Aerosol Module

Abstract. Accurately simulating secondary organic aerosols (SOA) in three-dimensional (3-D) air quality models is challenging due to the complexity of the physics and chemistry involved and the high computational demand required. A computationally-efficient yet accurate SOA module is necessary in 3-D applications for long-term simulations and real-time air quality forecasting. A coupled gas and aerosol box model (i.e., 0-D CMAQ-MADRID 2) is used to optimize relevant processes in order to develop such a SOA module. Solving the partitioning equations for condensable volatile organic compounds (VOCs) and calculating their activity coefficients in the multicomponent mixtures are identified to be the most computationally-expensive processes. The two processes can be speeded up by relaxing the error tolerance levels and reducing the maximum number of iterations of the numerical solver for the partitioning equations for organic species; conditionally activating organic-inorganic interactions; and parameterizing the calculation of activity coefficients for organic mixtures in the hydrophilic module. The optimal speed-up method can reduce the total CPU cost by up to a factor of 31.4 from benchmark under the rural conditions with 2 ppb isoprene and by factors of 10–71 under various test conditions with 2–10 ppb isoprene and >40% relative humidity while maintaining ±15% deviation. These speed-up methods are applicable to other SOA modules that are based on partitioning theories.

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Air Quality during New Year’s Eve: A Biomonitoring Study with Moss

Atmosphere ◽

10.3390/atmos12080975 ◽

2021 ◽

Vol 12 (8) ◽

pp. 975

Author(s):

Paweł Świsłowski ◽

Zbigniew Ziembik ◽

Małgorzata Rajfur

Keyword(s):

Heavy Metals ◽

Air Quality ◽

Atmospheric Aerosol ◽

Point Sources ◽

Accumulation Factor ◽

Active Biomonitoring ◽

Aerosol Pollution ◽

New Year’S Eve ◽

Short And Long Term

Mosses are one of the best bioindicators in the assessment of atmospheric aerosol pollution by heavy metals. Studies using mosses allow both short- and long-term air quality monitoring. The increasing contamination of the environment (including air) is causing a search for new, cheap and effective methods of monitoring its condition. Once such method is the use of mosses in active biomonitoring. The aim of the study was to assess the atmospheric aerosol pollution with selected heavy metals (Ni, Cu, Zn, Cd, Hg and Pb) from the smoke of fireworks used during New Year’s Eve in the years 2019/2020 and 2020/2021. In studies a biomonitoring moss-bag method with moss Pleurozium schreberi (Willd. ex Brid.) Mitt. genus Pleurozium was used. The research was conducted in the town Prószków (5 km in south direction from Opole, opolskie voivodship, Poland). The moss was exposed 14 days before 31 December (from 17 to 30 of December), on New Year’s Eve (31 December and 1 January) and 2 weeks after the New Year (from 2–15 January). Higher concentrations of analysed elements were determined in samples exposed during New Year’s Eve. Increases in concentrations were demonstrated by analysis of the Relative Accumulation Factor (RAF). The results indicate that the use of fireworks during New Year’s Eve causes an increase in air pollution with heavy metals. In addition, it was shown that the COVID-19 induced restrictions during New Year’s Eve 2020 resulted in a reduction of heavy metal content in moss samples and thus in lower atmospheric aerosol pollution with these analytes. The study confirmed moss usefulness in monitoring of atmospheric aerosol pollution from point sources.

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